Film for color cinematography.



P. D. BREWSTER.

FILM Foa COLOR clNEMAToGRAPHY.

APPLICATION FILED IUNE24, 1914. 1,222,925, Patented Apr. 17, 1917.

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FERCY D. BREWSTER, OF EAST ORANGE, -NEW JERSEY.

FILM FOR COLOR CINEMATOGRAPHY.

Specification of Letters Patent.

Patented Apr. 1*?, 1917.

Application filed J' une 24, 1914. Serial No. 846,966.

filed May 29, 1914, for the production of two negative films, eachhaving a separate color record, from which a positive film sensitized onboth sides can be printed to record one color or group of colors on oneside and another color or group of colors on the other side, therebyproducing a final result like that described in my co-pendingapplications Serial No. 747 ,712, filed February 11, 1913, and SerialNo. 843,351, filed June 6, 1914; that is, a two-color film with adifferent color on each side.

Several convenient and effective forms of the invention are illustratedin the accompanying drawings, in which- Figures 1, 2 and 3 show threeembodiments in cross section. Fig. ,4 is a. detail plan view of a spacerused to separate the two strips of film. Figs. 5 and 6 are plan views ofthe film shown in Figs. 1 and 2, respectively. Fig. 7 is a plan view ofa separator that may be used in Fig. 3. Fig. 8 is a sectional plan viewof a camera suitable for utilizing film of the types contemplated by thepresent invention. Fig. 9 is a plan View of the refiecting andtransmitting surface of one of the prisms used in the camera.

My improved film comprises two transparent supports or films 4, 6,superposed one on the'other and having color-sensitive emulsions 5, 7,with a spacer 8 and a separator 9 between the two films. The twoemulsions may both be panchromatic; but I refer to have one sensitizedchiefly for light of one or more colors above, say, yellowgreen of thespectrum, and the other for colors below yellow-green. Of course thedividing line in color-sensitiveness can be at any other desired point'in the spectrum. The emulsions may be color sensitive when coated orthey may be treated with dye baths of well known compositions aftercoating,hsuch as eosine or erythrosine for the green sensitiveness, anda derivative of cyanine for the red. It is usually necessary t0 filterout the ultra-violet, violet and part of the blue from the light beforeit reaches the red-sensitized film, as even specially dyetreatedemulsions are more or" less sensitive to these colors. The same systemof color sensitiveness may be applied to any of the film describedherein. I

The emulsions may be on the outside, as in Fig. 1, or on the insidefacing each other, as in iFig. 2. The two films and the spacer areattached to each other in any preferred .manner; for example, they maybe laced together through the holes 19, 19, by the lacing 19, Figs. 1and 5. The separator 9 may be integral with the space-r, as in Fig. 7,or it may be separate, as in Figs. 1 and 2, but it should be made of amaterial sufficiently opaque or colored to prevent the passage ofmaterial amount of light.

The function of the spacer between the two films is to maintain aseparation between the films equal to the thickness of the positive filmupon which the pictures are made from the negative; and the function, ofthe separator is to prevent the passage of any light through one filmagainst the other and -to maintain the films, during eXposure,fiat

and in the same relative positions that they will occupy when thepositiveY is being print-' ed, so that proper registration of the imagewill be secured.

In cinematographic work, for which the film is primarily intended, greataccuracy must be attained, as the small picture (an inch bythree-fourths of an inch in size) is enlarged ahundred and twenty to ahundred and fifty diameters, or fourteen thousand to twenty-two thousandtimes. Hence an error of a thousandth of an inch on the film amounts tofrom an eighth to a `sixth of an inch on the screen, which causes lackof sharpness and banding of colors. It is therefore important to makethespacer of a thickness as nearly as possible equal to arator simply acts'as a dummy for the posi-v tive nlm while the exposure of the two nega-,tive films is being edected.

After exposure, the two iilms are separated, as by removing the lacing19a, and are developed and fined, and (if desired) stained. The filmsare then reassembled with the spacer between as before, but without theseparator. (1f the separator and spacer were originally in one piecekthey must be cut apart.) The positive film, coated on both sides withlight-sensitive emulsions, is now placed between the negative lms inplace of the separatory and is printed on l both sides through thenegative films.

The two lms and the spacer can be inseparably fastened together alongone edge (as by gluing or cementing, or by pinning as at 19h, Figs. 2and 6) in which case the two films can be held open along the oppositeedge during development and such other treatment (fixing and staining)as may be desired; the separator being first removed, especially if theemulsions are on the inner surfaces of the lms. 1n printing, the twolms, fastened together along one edge,.are opened or spread apart alongthe other to receive 'the positive lm.

A plan view of a combined spacer and separator is shown in Fig. 7. Likethe separators in Figs. 1, 2, 5 and 6, it is perforated with standardsprocket holes (10, 10) used in cinematographic film, and, also providedwith a series of holes 11, 11, along which the separator may be tornfrom the spacer. rlfhe standardholes 10, 10 are preferably punched inthe lms and separator simultaneously, so as to insure an even feed offilm through the film gate, as will be readily understood.

Fig. 3 illustrates in cross section a single film of about double the'standard width, bent to form a double lm with a separator Y9 between. Aspacer 8 may be also incorporated between the lms and held in place byany convenient means.' 1f Celluloid be used for the film support, it canreadily be 'bent by the local application of heat along the line onwhich thebend is to be made. 1f the lm be placed in contact with a tubecontaining'steam or hot water the celluloid may f be readily bent and ifthis heat be applied v f' where the pictures are to be talren will notbe carefully, the emulsions on the portions aected as there willordinarily be a margin of about an inch between the two .series ofpictures. This form of double Elm is denaaaeaa veloped, etc., and isused in printing, in the same manner as the double film shown in Fig. 2.

A type of camera that may be used for exposing the negative film isshown in Fig. 8, and comprises a casing 12, provided with lens 13 anddiaphragm 14. rFhe light from the lens passes into the prism 15, andpart of `it is reflected from the surface 23 through filter 16 (adaptedto permit the passage of light of the red group of colors) in prism 17and is reflected by surface 28 of prism 1'? against the red sensitizedemulsion 2 6 on film 29m the film gate 18; while the other portion ofthe light passes through prism 2O and filter 21 (adapted to permit thepassage of light of the green group of colors),

` into prism 22 and is reflected from surface will be reflected whilethe portions cementedl together with the balsam will transmit the light.Any desired proportion of reflected and transmitted light may be securedin-this way.

As methods of intermittently feeding the lilm through the iilm gate arewell known in the art, it is not necessary to illustrate or describe thesame herein. 1 do not claim the apparatus described, such as the camera,prism and redecting systems.

lf vpanchromatic film be used, suitable light filters, as 16, 21, shouldbe interposed in the paths of the rays', so as to permit light of onlythe desired colors from reaching the respective emulsions.

The line of perforations 11, 11 (Fig. 7) in the spacer or separator maybe omitted and the spacer otherwise weakened along that line in anymanner, so ythat the spacer may be readily torn along the line ofweakness.

Inasmuch 'as any detachment of the two lms from each other for thepurpose of dedescribed as permanently fastened together,

to distinguish from prior schemes in which two films are attached to anintermediate yfugitive element. Insuch schemes (as for example in IveslPatent No. 927,244, dated July 6, 1909), the negatives are notreassembled after development and fixing, as they were before, but areused separately for printing separate positives which are then combined.

It is to be understood that the invention is not limited to theprocedure and apparatus herein specifically described but may bepractised in other Ways without departure from its spirit.

I claim:

l. As a new article 4of manufacture in the art of color photography,photographic film for the purpose described, comprising twocolor-sensitive films superposed one on the other and provided withmeans for holding the two in the same relative positions during exposurein a camera and during subsequent printing operations, and capable ofopening along one edge for the insertion of another film between the twofor printing purposes.

2. As a new article of manufacture in the art of color photography,`photographic film for the purpose described, comprising t-wo films, onesensitized for one or more colors and the second for one or more colorsdifferent from the first, the two films being superposed on each otherand provided with means to hold the two in the same relative positionsduring exposure in a camera and during subsequent printing operations,and capable of opening along one edge to permit the insertion of anotherfilm between the two for printing purposes.

3. As a new article of manufacture in the art of color photography,photographie film for the purpose described, comprising twocolor-sensitive films superposed one on the other and spaced apart, andprovided with means for holding the films in the same relative positionsduring exposure in a camera l and during subsequent printing operations,

but permitting the two films to open along one edge for the insertion ofanother film between the two for printing purposes.

4. As a new article of manufacture in the art of color photography,photographic film comprising two superposed color-sensitive films, aspacer between the two films, and means fastening the spacer and the twofilms together alongl one edge of the latter and permitting the films toopen along the other' edge for the insertion of a third film between theother two.

5. As a new art of color photography, photographic lm comprising twosuperposed color-sensitive films, a permanent spacer between the twofilms along one edge thereof, the films and article of manufacture inthe the spacer being fastened together, and a removable separatorarranged between the twoV films and extending over the areas thereofthat are to be exposed to light.

6. As a new article of manufacture in the art of color photography,photographic film comprising two superposed color-sensitive films, aspacer arranged between the two films along one edge and permanently secured thereto, and a separator detachably connected to the spacer andextending therefrom toward the opposite edge of the film.

7. As a new article of manufacture in the art of color-cinematography,cinematogra-phic film comprising two long and relative narrowcolor-sensitive films superposed on each other, and a spacer between thetwo films along one edge thereof, the films and the spacer beingpermanently fastened together but permitting the films to open along theopposite edge to receive a third film for printing purposes.

8. As a new article of manufacture in the art of color -cinematography,cinematographic lm comprising two long and relatively narrowcolor-sensitive films superposed on each other, a spacer between thefilms along one edge thereof, the two films and the spacer beingpermanently fastened together, and a removable separator between the twofilms and extending over the areas thereof that are to be exposed tolight.

9. As a new article of manufacture in the art of color cinematography,cinematographic film comprising two color-sensitive films su erposed oneach other, a permanent spacer etween the films along one edge thereof,and a removable separator arranged between the two films and extendingover the areas thereof that are to be exposed to light.

10. As a new article of manufacture in the art of colorcinematography,cinematographie film comprising two color-sensitive films superposed oneach other, a spacer arranged between the films along one edge thereofand permanently fastened thereto, and a separator between the films,detachably connected to the spacer and extending toward the oppositeedge.

In testimony whereof, I have signed my name to this specification in thepresence of two subscribing witnesses, this 23rd day of June, 1914.

PERCY D. BREVSTER.

Witnesses:

A. S. Bimws'rnn, C. ODoNoGHUn.

